Control of potato soft rot caused by Pectobacterium carotovorum and Pectobacterium atrosepticum by Moroccan actinobacteria isolates

Abstract

Pectobacterium carotovorum and Pectobacterium atrosepticum are dreadful causal agents of potato soft rot. Actually, there are no efficient bactericides used to protect potato against Pectobacterium spp. Biological control using actinobacteria could be an interesting approach to manage this disease. Thus, two hundred actinobacteria isolated from Moroccan habitats were tested for their ability to inhibit in vitro 4 environmental Pectobacterium strains and the two reference strains (P. carotovorum CFBP 5890 and P. atrosepticum CFBP 5889). Eight percent of these isolates were active against at least one of the tested pathogens and only 2% exhibited an antimicrobial activity against all tested Pectobacterium strains. Four bioactive isolates having the greatest pathogen inhibitory capabilities and classified as belonging to the genus Streptomyces species through 16S rDNA analysis were subsequently tested for their ability to reduce in vivo soft rot symptoms on potato slices of Bintje, Yukon Gold, Russet and Norland cultivars caused by the two pathogens P. carotovorum and P. atrosepticum. This test was carried out by using biomass inoculums and culture filtrate of the isolates as treatment. Among these, strain Streptomyces sp. OE7, reduced by 65-94% symptom severity caused by the two pathogens on potato slices. Streptomyces OE7 showed a potential for controlling soft rot on potato slices and could be useful in an integrated control program against potato soft rot pathogens in the objective to reduce treatments with chemical compounds.

Trichokonins fromTrichoderma pseudokoningiiSMF2 induce resistance against Gram-negativePectobacterium carotovorumsubsp. carotovorumin Chinese cabbage

“…carotovorum (Pcc, formerly known as Erwinia carotovorum subsp. carotovorum), a Gram-negative bacterium, is the casual agent of bacterial soft rot, a severe disease of field crops (corn, rice, and sugar beet), ornamental plants (begonia, dieffenbachia, dahlia, and philodendron) and vegetables (potato, tomato, onion, crucifers) (Aysan et al, 2003;Fiori & Schiaffino, 2004;Zhang et al,2007;Baz et al, 2012). Chinese cabbage (Brassica rapa L. ssp.…”

Calcium- and ROS-mediated defence responses in BY2 tobacco cells by nonpathogenic Streptomyces sp

“…2012) and (ii) they secrete different metabolite profiles as judged by their high (strain OE7) and low (strain OE53) antimicrobial activities against P. atrosepticum development in vitro (Fig. 1a) (Baz et al. 2012).…”

“…strains OE7 and OE53 were isolated from Moroccan rhizospheric soils. The analysis of 16S rDNA sequences indicated that OE7 isolate shared 99–100% maximal sequence identity with Streptomyces griseus and Streptomyces ornatus and that OE53 exhibited 99% maximal sequence identity to Streptomyces puniceus and Streptomyces californicus (Baz et al. 2012).…”

“…2012). Phylogenetic trees also indicate that these strains do not belong to Streptomyces scabiei , the pathogenic agent of common scab in potato (Baz et al. 2012).…”

Uso de antagonistas e produtos alternativos no manejo pós-colheita de podridão mole em pimentão

“…A utilização de leveduras e bactérias antagonistas no manejo de podridões em pós-colheita tem sido estudada por vários pesquisadores (BAZ et al, 2012;GOMES;SILVEIRA;MARIANO, 2005), existindo os produtos comerciais Aspire ® e Bio-save 110 ® , à base de Candida oleophila I-182 e Pseudomonas syringae, respectivamente, para o manejo de diversas doenças fúngicas em diferentes culturas (SENHOR et al, 2009). Considerando a carência de pesquisas com uso de fosfitos para o controle de bactérias fitopatogênicas, bem como a importância econômica da podridão mole e visando reduzir as perdas pós-colheita em pimentão, o objetivo para desenvolver este trabalho foi avaliar o efeito de antagonistas e produtos alternativos no manejo da infecção causada por P. carotovorum subsp.…”